In a semiconductor device that controls a metal-oxide semiconductor (MOS) transistor connected to the output of a load, when the potential of a grounding terminal changes from a reference potential to an electrically open state, a malfunction in which the semiconductor device cannot turn off the output MOS transistor may occur.
Thus, a semiconductor device in which an auxiliary MOS transistor is connected between the gate and source of the output MOS transistor is known. In this semiconductor device, when the grounding terminal has an electrically open state, the auxiliary MOS transistor turns on, thus turning off the output MOS transistor.
However, as the electrically open state of the grounding terminal raises the potential of the grounding terminal up to a power-supply voltage, it becomes difficult to cause the auxiliary MOS transistor to turn on.